Hitting back at the Left Front for its continuous criticism of the India-United States nuclear agreement, Union Science and Technology Minister Kapil Sibal on Saturday wondered whether the Left had a hidden agenda behind its opposition.

"Left's opposition to the 123 agreement is for opposition's sake. If they have a hidden agenda, the people of this country must know," Sibal said in Kolkata on Saturday.

"If they are anti-America and they don't want the deal on that account, that also should be made clear to the people of the country," he said.

Reiterating that the United Progressive Alliance government was going ahead with the deal, Sibal said, "Nobody said we are stopping the deal. We will take into account the concerns of the left before operationalising it. But there is no area to renegotiate the deal."

He added, "When the whole world is moving forward, why are the Left pulling India back? We want to work with the Left and provide a stable government till its full term. We await their response."

Criticising the Communist Part of India-Marxist, which has been insisting on the ratification of all treaties and agreements by the Parliament, Sibal said, "That is not the law. That is not the Constitution. In India's entire history, has any international treaty been ratified by Parliament? Let them give just one example.

Claiming that the deal was in national interest, he said, "We are neither anti-America nor anti anybody. We will do everything to take India forward."

Sibal pointed out that before India signed the World Trade Organisation agreement, the Left had said it was against national interest.

"Are they going to teach us a lesson in patriotism and nationalism?" asked Sibal.